In a case of aseptic filling of tea, fruit juice beverages, coffee beverages, and the like, the inside and the outside of a container to be filled with such a beverage needs to be sterilized before the container is filled with the beverage. Therefore, in a method of sterilizing a molded container such as a paper container or a plastic container such as a PET bottle, an aqueous solution of peracetic acid (with a rational formula of CH3C(═O)OOH) or an aqueous solution of hydrogen peroxide (H2O2) is mainly used. In addition, in a case where a container as a sterilization object has a deep bottom shape or an uneven shape, a method of sterilizing the container by spraying a sterilant toward the sterilization object and drying the container is known. In addition, a method of sterilizing a container by heating a sterilant to its boiling point or higher so as to be vaporized, spraying the vaporized sterilant into the air to be condensed which adheres to the container as fine mist, and drying the container is also known.
However, in the sterilization methods according to the related art, a high concentration of hydrogen peroxide is used, and thus the sterilizing ability is sufficient. However, the hydrogen peroxide adsorbs onto and penetrates into the surface layer of the container, and it takes time for the removal of the hydrogen peroxide. Therefore, the sterilization process cannot be shortened. Here, Patent Document 1 proposes, as a method of reliably performing sterilization at a high speed, a method of introducing a mist of hydrogen peroxide condensed and generated after temporarily vaporizing droplets of hydrogen peroxide into a pre-heated PET bottle and blowing hot air into the PET bottle.